The IK problem and its typical solutions

                        Roman Berka

                    berka@fel.cvut.cz


The inverse kinematics (IK) is often used in computer animation
applications.  The IK originates from the field of robotics and is
typically applied to rigid body models with articulated structure.

The IK problem appears during computation of angular velocities in
joints based on input values expressing the linear velocity of the
terminating joint called "end effector".  The solution usually leads
to inversion of a matrix called Jacobian which linearizes the relation
between angular and linear velocities of joints. Unfortunately, the
Jacobian corresponding to structures representing typical models
(e.g. human arm) is not directly invertible and this is a serious
complication which evoked many activities leading to several solutions
in 80's.

The talk will be devoted to the specification of the IK problem in
detail. Then the mostly used solutions will be presented and
compared. Finally, some tools will be shown.